Unbalanced/Balanced Operation; Mains Connection - BBE MAXCOM Owner's Manual

INSTALLATION
• IMPEDANCE
The input has an impedance of 60k Ohms and can be driven by most input sources.

UNbALANCED/bALANCED OPERATION

90% of all mistakes in audio installations can be attributed to incorrect and defective audio connections! In order
to utilize the MAXCOM to its full potential, please pay special attention to the following section. For better under-
standing, the technical difference between unbalanced and balanced systems must be clarified:
• THE UNbALANCED SYSTEM
Unbalanced operation is characterized by a single conductor shielded cable with the center conductor carrying
the signal and the shield at ground.
• THE bALANCED SYSTEM
A balanced operation is defined as a two conductor shielded cable, where each of the two center conductors carry
the signal but of opposite phase. They have equal but inverted potential differences from that of the ground.
The advantage of the balanced system is based on the effect that the differential amplifier in a subsequent
device suppresses all equal phased noise which has been induced during its transmission down the cable link.
However, the original signal will be amplified and retain all its original integrity.
In this way audio signals can be transmitted without interference or loss across long distances. Balanced or
unbalanced systems require different wiring. Please read the next section carefully and pay close attention to
the correct wiring requirements of the units in the audio chain.
• THE CORRECT WIRING FOR bALANCED OPERATION
If the Unit preceding the MAXCOM uses output balancing we recommend that you use balanced audio con-
nections. This will avoid interferences such as mains hum etc. For maximum hum rejection, you should avoid
common grounding, which means grounding the MAXCOM input and output.
We recommend that you connect the shield of the input ca-
ble to the ground of the signal source, making sure that the
shield is not connected to the MAXCOM input connector. At
the output, the shield of the cable is connected to the ground
of the MAXCOM, but making sure that the shield of the cor-
responding cable's end is not connected to the ground of the
subsequent unit. Generally speaking, the shield connection
will be tied to the source units, but not to destination units. If
you still develop hum, it may be helpful is some cases to con-
nect the shield on the input of the subsequent device also.

MAINS CONNECTION

The mains connection in the MAXCOM is made by using a mains cable and a standard IEC receptacle. It meets
all of the international safety certification requirements. Please make sure that all units have a proper ground
connection. For your own safety it is advisable not to remove the ground connection within the unit or at the sup-
ply, or fail to make this connection at all. The audio ground of the MAXCOM is internally capacitor decoupled to
isolate it from the supply earth. It is therefore not advantageous to attempt ground loop problem solving using
this method.
• OPERATING vOLTAGE
Before you switch on the MAXCOM, check that the AC mains voltage match that one shown on the back panel
of the unit.
• SAFETY FUSE REPLACEMENT
A safety fuse protects the unit from serious defects. If the fuse blows, this is a warning sign and always indicates
that the circuit is overloaded. The fault must always be repaired before the fuse is replaced.
If the safety fuse is faulty and needs replacing after the unit is repaired, please make sure that you replace it only
with the identical type and rating. NEVER use fuses of different ratings or cover faulty fuses with aluminium foil.
This can cause fire and electric shocks and will endanger your life and the lives of others.
The correct wiring of the balance system

END UNIT